Production of lubricating oils

ABSTRACT

A WHOLLY CATALYTIC ROUTE FOR THE PRODUCTION OF LUBRICATING OILS FOR PETROLEUM FEEDSTOCKS BOILING ABOVE 350*C. COMPRISES THE STEPS OF VI IMPROVEMENT OVER A CATALYST OF A GROUP VIA AND/OR GROUP VIII METAL ON A REFRACTORY OXIDE SUPPORT AND CATALYTIC DEWAXING OVER A CATALYST OF A GROUP VIA AND/OR GROUP VIII METAL ON LOW ALKALI METAL CONTENT MORDENITE. THE STEPS MAY BE IN EITHER ORDER BUT THE VI IMPROVEMENT STEP IS PREFERABLY FIRST. THE VI IMPROVEMENT STEP IS AT 650-850*F. AND 1000-3000 P.S.I.G. USING PREFERABLY, CO-MO OR SILICA ALUMINA AND THE CATALYTIC DEWAXING STEP IS AT 450-950* F. AND 100-3000 P.S.I.G. USING, PREFERABLY, PT ON DECATIONISED MORDENITE HAVING A SIO2;AL2O3 RATIO OF 14:1-50:1. DEPENDING ON THE FEEDSTOCK TO AND THE SEVERITY OF THE VI IMPROVEMENT STEP, LUBRICATING OIL PRODUCT FRACTIONS OF EITHER HIGH (75-100) OR SUPER HIGH (100-140) VI MAY BE PRODUCED.

United States Patent 3,663,423 PRODUCTION OF LUBRICATING OILS RobertNeil Bennett, Ashford, Richard Nigel Parker, Middlesex, and BernardWhiting Burbidge, Surrey, England, assignors to The British PetroleumCompany Limited, London, England No Drawing. Filed Mar. 14, 1969, Ser.No. 807,401 Claims priority, application Great Britain, Mar. 22, 1968,13,889/ 68 Int. Cl. Cg 13/02, 37/02 US. Cl. 208-59 6 Claims ABSTRACT OFTHE DISCLOSURE A wholly catalytic route for the production oflubricating oils for petroleum feedstocks boiling above 350 C. comprisesthe steps of VI improvement over a catalyst of a Group Vla and/ or GroupVIII metal on a refractory oxide support and catalytic dewaxing over acatalyst of a Group VIa. and/or Group VIII metal on low alkali metalcontent mordenite. The steps may be in either order but the VIimprovement step is preferably first.

The VI improvement step is at 650-850 F. and 1000-3000 p.s.i.g. usingpreferably, Co-Mo or silica alumina and the catalytic dewaxing step isat 450-950 F. and 100-3000 p.s.i.g. using, preferably, Pt ondecationised mordenite having a SiO :Al O ratio of 14:1-5021. Dependingon the feedstock to and the severity of the VI improvement step,lubricating oil product fractions of either high (75-100) or super high(100-140) VI may be produced.

This invention relates to the production of lubricating oils by a whollycatalytic route without the use of solvents.

As conventionally practised the production of lubrieating oils requiresthe steps of solvent extraction with e.g. furfural to remove aromaticsand improve the viscosity index, solvent dewaxing with e.g. an alkylketone to remove n-paraffins and improve the pour point and, possibly, afinishing treatment with acid, bauxite or clay to improve colour andcolour stability. Hydrocatalytic treatment to replace the acid, bauxiteor clay finishing treatment is now well established commercially butalthough it is acknowledged that solvent extraction of aromatics andsolvent dewaxing are expensive and complicated operations, progress atreplacing them with hydrocatalytic treatments has been slower. Onepossible reason for this is that the full economic advantages ofhydrocatalytic treatment can only be achieved when satisfactoryhydrocatalytic processes have been developed for both stages.

According to the present invention a wholly catalytic process for theproduction of lubricating oils from a petroleum feedstock boiling above350 C. without the use of solvents for aromatic and wax removalcomprises the steps of passing the oil over a catalyst comprising one ormore hydrogenating components selected from Groups VIa and VIII of thePeriodic Table on a refractory oxide support together with hydrogen at atemperature of from 650 to 850 F. and a pressure of from 1000 to 3000p.s.i.g. to give a material of reduced aromatic content and improvedviscosity index and also over a catalyst comprising one or morehydrogenating components selected from Groups VIa and VIII of thePeriodic Table incorporated with a crystalline mordenite of reducedalkali-metal con tent together with hydrogen at a temperature of from450 to 950 F. and a pressure of 100 to 3000 p.i.s.g. to give a materialof reduced wax content and improved pour point and recovering alubricating oil fraction of both improved viscosity index and improvedpour point.

The steps of viscosity index improvement and catalytic dewaxing may becarried out in either order. Preferably the viscosity index improvementstep precedes the catalytic dewaxing step. The abbreviation VI will beused hereinafter to refer to viscosity index.

The feedstock to the process is preferably a vacuum distillate fractionboiling within the range 350-600 C. Since lubricating oils are marketedin several grades with relatively narrow boiling ranges, distillation togive relatively narrow boiling range cuts is required at some stage. Inthe present invention, a wide boiling range cut may be used as feedstockand distillation into narrower cuts given after the first or secondhydrocatalytic treatment or distillation may take place before thehydrocatalytic treatment and individual cuts may be hydrotreated. Theformer route has the advantage of avoiding blocked operation but thelatter route has the advantage that optimum hydrotreating conditions maybe chosen for each cut.

Within the context of hydrocatalytic treatment for VI improvement, twogeneral processes are recognised. These are (i) a relatively mildtreatment to give a moderate VI improvement e.g. to 100 VI afterdewaxing with minimum breakdown and decrease in viscosity. Increase inVI of the product to bring it up to multi grade oil requirements, ifdesired, can be achieved by the use of known polymeric VI improvers.(ii) a more severe treatment with extensive breakdown and decrease inviscosity but giving a larger VI improvement e.g. greater than 100 VIafter dewaxing. A larger amount of lower boiling gas oil, kerosene andgasoline by-products are obtained with the more severe treatment.

Preferably the milder type (i) process is used with a distillatefeedstock boiling in the range 350-600 C. having a VI of 30 to and witha breakdown to products boiling below 350 C. of less than 30 percent wt.under the following ranges of conditions:

Temperature, F. 650-850 Pressure, psig 1000-3000 Space velocity,v./v./hr. 0.1-5

Hydrogen treating rate, s.c.f./b. 2000-10,000

If the VI improvement step precedes the catalytic dewaxing step the VIof the product boiling above 350 C. should be in the range 90-120 toallow for some reduction in VI in the subsequent catalytic dewaxingstep. If it follows the catalytic dewaxing step this dewaxinsg step willalready have lowered the VI of the original feedstock, and the VI ofthe. product boiling above 350 C. from the VI improvement step should befrom 75 to 100.

The refractory inorganic oxide support may be one or more oxides ofelements of Groups II, III or IV of the Periodic Table, and may containhalogen. Preferably the amounts of the components of the support arechosen from the following ranges:

Percent wt. A1 0 50-100 Si0 0-50 B 0 0-25 F or Cl 0-10 Percent wt.(expressed as metal) Group VIa metals 2-25 Iron group metals 1-15Platinum group metals 0.1-5

Preferred hydrogenating components are from 2-25 percent wt. ofmolybdenum (expressed as metal but present as oxide or sulphide) and1-15 percent wt. of nickel and/or cobalt again expressed as metal butpresent as oxide or sulphide.

With the more severe type of VI improvement process the preferredfeedstocks boil with the range 450-600 C. and have a VI of 30-90. Thefollowing ranges of condi tions may be used to give a conversion toproducts boiling below 350 C. of 30-80 percent wt.

Temperature, F. 725-850 Pressure, p.s.i.g 1000-3000 Space velocity,v./v./ hr 0.1-5 Hydrogen treating rate, s.c.f./b. 2000-10,000

If the VI improvement step precedes the catalytic dewaxin'g step the VIof the product boiling above 350 C. should be in the range 120-160 toallow for some reduction on VI in the subsequent catalytic dewaxingstep. 'If it follows the catalytic dewaxing step, this dewaxing stepwill already have lowered the VI of the original feedstock and the VI ofthe product boiling above 350 C. from the VI improvement step should befrom 100 to 140.

The catalyst is preferably the same as for the milder type (i) processboth in terms of the hydrogenating component and the support. Thesupport may, however, be more acidic than the preferred support of themilder process and may consist for example of 60-90 percent wt. Si and10-40 percent wt. A1 0 or 85-90 percent Wt. A1 0 and 5-15 percent wt.halogen.

It will be appreciated that the acidity of the catalyst support, thetemperature, pressure and space velocity all affect the severity of theoperation and hence the degree of VI increase and viscosity decreaseobtained and that any one or more of these may be varied as required.Preferably the space velocity is lower for the more severe type (ii)process than for the milder type (i) process.

The term VI as used in this specification means viscosity index asmeasured by ASTM D567. Currently two methods are in use ASTM Test MethodD567 and the VIE extended method ASTM D2270. Appreciable differences innumbers are possible between the two methods when testing the same oil.

In addition to VI improvement, sulphur and nitrogen in the feedstockwill be converted, if present, to H 8 and NH The latter is desirablyremoved (by scrubbing with water) from any gas recycled and both H 8 andNH are desirably removed from any gas passing to the hydrocatalyticdewaxing stage.

The catalytic dewaxin'g step operates selectively to break down theparaifinic waxes to lower boiling materials which are readily removablefrom the remainder of the lubricating oil feedstock, which remainssubstantially unaffected. It may follow the general procedure describedin UK. patent specifications Nos. 1,088,933; 1,134,014 and 1,134,015.The term paraflinic wax refers to those waxy hydrocarbons which have along straight chain as part of their structure, e.g. particularlyn-paraffins themselves but also very slightly branched chainhydrocarbons, and cyclic hydrocarbons having an unbranched alkylside-chain. The selective breakdown of the paratfin wax hydrocarbons isdue to the nature of the mordenite based catalyst which promotes theselective attack of these hydrocarbons but not of the other hydrocarbonspresent in the feedstock.

Suitable process conditions for the catalytic dewaxing include besides atemperature within the range 450-950 F. and a pressure within the range100-3 000 p.s.i.g. as indicated above, a space velocit between 0.1-20.0v./v./hr., and a gas rate of SOD-30,000 s.c.f. of hydrogen.

Preferred catalytic dewaxing conditions are:

Temperature, F. 500-800 Space velocity, v./v./hr. (LS-10,0 Pressure,p.s.i.g 500-3000 Hydrogen treating, s.c.f./b. 5000-15,000

The term crystalline mordenite of reduced alkali metal conten means,preferably, a mordenite with an alkali metal content of less than 3percent wt. The deficiency of alkali metal cations can be made up withother metal cations for example Group II metal cations, particularlymagnesium or rare earth metal cations. Preferably however the mordeniteis a decationised mordenite which means a mordenite having a deficiencyof metal cations. An alternative term in the art is hydrogen mordenite,since it is assumed that when metal cations are removed they arereplaced by hydrogen ions. However, since it is not possible to detectthe presence of hydrogen ions in zeolites, the precise structure remainsin doubt. A cation deficiency can, on the other hand, be readilymeasured by analysis of the metallic elements present in the zeolite.

Natural or freshly prepared synthetic mordenite has the formula:

where Me is a metal cation, m is the valency of the cation and X isvariable between nil and 7 depending on the thermal history of thesample. Me is commonly sodium and in one common form of decationisationsodium mordenite is base exchanged with ammonium cations. The ammoniumform is then heated to drive off ammonia, leaving behind the hydrogenform or decationised mordenite. According to the second method themordenite may be treated with a mineral acid, for example hydrochloricor sulphuric acid, in order directly to decationise the mordenite. Acombination of acid treatment and am monium treatment can also be used.

Preferably the decationised mordenite used in the present invention hasa higher than normal silicazalumina ratio of at least 14:1. In specificexamples ratios of as high as :1 have been obtained and a practicalupper limit may thus be :1. Particularly preferred silicazalumina ratiosare in the range 14:1 to 50:1.

It has been found that certain decationisation treatments removealuminium as Well as the expected metal cations and desirably thereforethe mordenite used in the present invention having a higher than normalsilicazalumina ratio is obtained by treatment of a metalcationcontaining mordenite, particularly sodium mordenite, with a strongacid, for example sulphuric or hydrochloric acid, of from 5-50 percentwt. strength and preferably from 10 to 20 percent wt. strength. A singletreatment or two or more successive treatments may be given with acidsof the strengths stated above.

A convenient method of treatment is to treat the mordenite with acidunder reflux for a period of 2-12 hours.

In the decationised mordenite the residual metal cation content, forexample the sodium cation content, should be less than 2 percent wt. ofthe mordenite and preferably less than 1.5 percent wt. of the mordenite.

It should be emphasised that mordenites with higher than normalsilicazalumina ratios retain the crystal structure of mordenite and arenot significantly altered in terms of physical strength, stability orcrystallinity.

The hydrogenating component is preferably a platinum group metal,particularly platinum or palladium, and it is preferably added byion-exchange. Preferably the mordenite is aged in water before addingthe platinum group metal as described in the specification of UK.application No. 4421/ 6-8, which application corresponds to US. patentapplication Ser. No. 790,829, filed Jan. 13, 1969 and now Pat.3,553,103. The amount of the platinum group metal is preferably withinthe range 0.01 to 10 percent Wt., particularly 0.1 to 5 percent wt.However, iron group metals, particularly nickel, also give usefulresults and they may be used in amounts similar to the platinum groupmetals. Mixtures of certain Group VI and VIII metals and compounds mayalso be used, e. g. cobalt and molybdenum.

The catalyst is preferably calcined at for example 250- 600 C. beforeuse to remove any water and to eliminate any ligands attached to thehydrogenation component.

The catalytic dewaxing step is capable of treating lubricating oilfractions with pour points of from 60 to 120 F. to give products of from+40 to 60 F. Some reduction of VI is to be expected since n-paraffinsare materials of high VI.

The lubricating oil product from the dewaxing stage is stabilised toremove the breakdown products, which consist largely of C and Cparaflins, which are valuable for use in LPG and as petrochemicalfeedstocks. There may be a small amount of C -C hydrocarbons produced,but it is a particular feature of the catalyst of the present inventionthat it does not give large amounts of C hydrocarbons in the gasolineand middle distillate boiling ranges and is not a hydrocracking catalystas generally understood.

As stated above, lubricating oils are usually given a finishingtreatment to improve colour and colour stability which is now usually amild hydrocatalytic treatment known as hydrofinishing. It has been foundthat the catalytic dewaxing process used in the present invention itselfaffects improvement in colour and colour stability so that it may bepossible to dispense with a finishing step altogether.

The invention is illustrated by the following examples.

EXAMPLE 1 A Kuwait wax distillate having a 2% TBP point of 350 C. and anend point of 560 C. and having the inspection data shown in Table 1below was hydrogenated material beoling below 240 C. had the followinginspection data:

Yield of product boiling above 371 C., percent wt. 74.1

Kinematic viscosity at 100 F., cs 22.3 Kinematic viscosity at 210 F.,cs. 4.29 Viscosity index 111 Four point, F 90 Sulphur content, percentwt 0.06 Wax content, percent wt. 13.8 Wax melting point, F. 124

The topped product was then passed to a catalytic dewaxing stage using aplatinum-decationised mordenite catalyst having the followingcomposition (calculated on material stable at 550 C.) Platinum perce'ntwt 0.62 Aluminium do 5.08 Silicon do 40.3 Sodium do 0.93 SiO :Al O molratio 15.3 Surface area m /g 425 Pore volume ml./g 0.22

The space velocity and gas rate were varied during the run to assess theeffect of these variables. Temperature and pressure were kept constant.After the catalytic de- Waxing the product was distilled to removematerial boiling below 371 C. and the material boiling above 371 C. wasvacuum distilled to give 6 fractions. The process conditions used, theyields obtained and inspecunder the conditions shown in Table l. tiondata on the 6 fractions are given in Table 2 below.

TABLE 2 Conditions for catalytic dewaxing' Pressure, p.s.i.g 1, 000Temperature, F-.. 700

Space velocity, v.lv./h 2. 0 4, Gas rate s.e.f./bb1 10,000 5,000Inspection ata on dewaxed liquid product:

Pour point, F -40 Average yield on feed, percent wt. 71. 0 75. 0 Yieldof residue 371 C. on feed,

percent wt 52. 0 50, 8

Yield on Yield Yield on Yield residue, on feed, Pour residue, on feed,Pour percent percent KV,100 KV, 210 point, percent percent KV, 100 KV,210 point., wt. wt. F., est. F., est. VI F. wt. wt. F., est. F., est. VIF. Inspection data on fractions ex residue i 1 17 1 s 9 a0 a9 4 3 rec on9 2 55 17.1 8.7 85.51 4. Fraction 2- 16.9 8.8 36. 97 4.97 42 -45 16.88.5 40.39 5. 2 53 i3 Fraction 3- 17.8 9.3 44.90 5.72 63 -40 16.9 8.646.91 5.96 69 -15 Fraction 4--- 15.9 8.3 57.83 6. 84 74 -25 16.7 8.557.49 6.95 80 0 Fraction 5--- 16.3 8.4 71.37 8.19 89 0 16.7 8.5 69.738.07 89 15 Fraetionfi (residue)- 16.0 8.3 118.4 11.85 96 25 15.8 8.0108.8 11.35 99 30 TABLE 1 Inspection data on feed; Fractions 5 and 6 ofTable 2 are products of increased Kinematic viscosity VI and improvedpour points according to the invention. 100 F., cst. 75.00 Fra tions'1-4 which have improved pour points but not 210 F., cst 7.92 increasedVI are particularly suitable for use as very low VISCOSItXIBdEX 73-00pour point industrial oils -*(e.g. transformer oils). Pour point, F. 95Sulphur content, percent wt. 2.76 EXAMPLE 2 Nitrogen content, percentwt. 0.10 Wax q f p Wt A Kuwait wax distillate fraction having theinspection Hydrogenation conditions employed:

Catalyst (1) data shown in Table 3 below was hydrogenated underPressure, psig 1500 the conditions shown in Table 3. Temperature, F. 770Space velocity, v./v./h. 1.5 T B E 3 Recycle gas rate, s.c.f./bbl. 7500Recycle gas Scrubbing 2 Inspection data on feed: Hydrogen consumption,s.c.f./bbl 750 Kinematlc vlscoslty O Cove/silica alumina. Catalystcomposition was: F" 4017 I0 labd percent WE. 210 F., 68- 5-'6 1 0 y61111111 percen W iilicon 9.0 percent wt. Vlscoslty Index 82 luminaBalance. e Surface are 331 mF/g. Pour polnt F' 85 "A For ,5 extrudates.Sulphur content, percent wt. 2.42 a remov :Nitrogen content, percent wt.0.08 The product from this stage after topping to remove Wax content,percent wt. 12.6

Hydrogenation conditions employed:

CoMo/SiAl (as in Example 1).

2 Ammonia removal.

The total liquid product from this hydrogenation step was then strippedof H 8 and passed to a catalytic dewaxing stage usingplatinum-decationized mordenite (as Periodic Table incorporated with acrystalline decationised mordenite having a sodium content of less than2 percent wt., said mordenite having a SiO :Al O ratio of from 14:1 to50:1, at a temperature of from 450 to 950 F., a pressure of 100 to 3000p.s.i.g., a space velocity of 01-200 v./v./hr. and a hydrogen treatingrate of 500- 30,000 s.c.f./b. at which there is produced a material ofreduced wax content boiling above 350 C. and having a reduced pour pointand an improved viscosity index of from 75 to 140; and recovering afraction having an improved viscosity index of at least 7 points higherthan that of the original feedstock and a pour point of at least below15 F.

2. A process as claimed in claim 1 wherein the feedin Example 1) a hdewaxjng catalyst, 15 stock is a vacuum distillate fraction boilingwithin the After the catalytic dewaxing step the product was dis- 'fhawng VI P 30 t0 90 d h tilled to remove material boiling below 371 C.,and the vlswslty Index lmproverrient p 15 carried out at materialboiling above 371 C. was vacuum distilled to 1000-3000 P- and 0'- give 5fr ti n 10,000 s.c.f./b. to a conversion of less than 30 percent Thedewaxing conditions used, the yields obtained and 20 of P u bollmg below350 C the inspection data on the 5 fractions are given in Table Processas cliflllled 111 clalfll 1 l feed- 4 b l stock is a vacuum dlstillatefraction boiling within the TABLE 4 etreatsstarters: 1.

Temperature, F 700 700 Space velocity, v./v./h 4. 0 6.0 Gas rate,s.c.t.fbbl 10, 000 Liquid yield on dewaxing 73. 3 75 Ingple eton data ondewaxed liquid product Ponr polnt, F Yield of residue 371 C. on feed,percent weight 47. 4 0

m Yield on 33 453 original Yield wax Yield wax on distillate ondistillate residue, feedstock, KV, KV, Pour residue, feedstock, KV, KV,Pour percent percent 100, 210, point, percent percent 100, 210, point,wt. w cs. cs. F. wt. wt es. cs. VI

ti t

20.9 9.6 23.81 3.97 44 -50 22.1 10.9 29.04 4.69 79 -1o Fraction 2-- 20.19.45 27. 00 4.4 64. -35 22.3 11.1 30.98 4.96 90 5 Fraction 3-. 20.3 9.330. 56 4. 79 76 -30 23.5 11.6 32.91 5.21 96 15 Fraction4 19.9 0.1 36.885.48 90 -10 21.1 10.4 36.98 5.70 103 20 Fractionli (residu 18.2 5.457.81 7.47 99 5 10.8 5.2 58.08 7.83 100 Again it will be seen thatfractions of high VI and low range 450-600 C. having a VI of 30 o 90 andthe vispour point are obtained. From the fractions on the right cosityindex improvement step is carried out at 725-850 hand side of the table,32.5 percent wt. (based on the R, 1000-3000 p.s.i.g., 0.1-5 v./v./hr.and 2000l0,000

original wax distillate feedstock) of a lubricating oil of s.c.f./ b. toa conversion of 30 to 80 percent wt. of prod- 5.4 cs. viscosity, 100 VIand 15 F. pour point can be ucts boiling below 350 C.

obtained, which (apart from a marginally high pour 4. A process asclaimed in claim 1 wherein the vispoint) is within the specification for65/ 1000 grade lubricosity index improvement step catalyst comprisesfrom eating oil. 2-25 percent wt. of molybdenum and 1-15 percent wt.

We claim: of nickel and/ or cobalt on an alurninazsilica support hav- 1.A wholly catalytic process for the production from ing from 50-90percent wt. of alumina and 10-50 percent a wax-containing petroleumfeedstock boiling in the wt. of silica.

range 350-600" C. and having a viscosity index of from 5. A process asclaimed in claim 1 wherein the catalytic 30 to 90, of an improvedlubricating oil boiling above dewaxing step is carried out at 500-800"F., 500-3000 350 C. and having a reduced pour point and an imp.s.i.g.,0.5-10 v./v./hr. and 5000-15000 s.c.f./b. using proved viscosity indexof from 75 to 140, in the absence a catalyst comprising from 0.01-10percent wt. of a of any solvent refining for the removal of aromaticsand P m gr p metal iHCOTPOIated with the crystalline wax from thefeedstock, said process comprising the Steps decationised mordenitehaving a sodium cation content of passing the feedstock, together withthe hydrogen, of less than 2percent wt.

over a viscosity index improvement catalyst comprising 6. A whollycatalytic process for the production of an one or more hydrogenatingcomponents selected from improved lubricating oil boiling above 350 C.and having Groups VIa and VIII of the Periodic Table, on a refracareduced pour point and an improved viscosity index of tory oxidesupport, at a temperature of from 650' to 850 from 75 to 140, from awax-containing petroleum feed- R, a pressure of from 1000 to 3000p.s.i.g., a space stock boiling in the range 350-600 C. and having avisvelocity of 0.1-5 v./v./hr. and a hydrogen treating rate cosity indexof from 30 to 90, in the absence of any of 2000-l0,000 s.c.f./b. atwhich there is produced a solvent refining of the feedstock for theremoval of material of reduced aromatic content boiling above 350aromatics and wax from the feedstock, said process com- C. and having animproved viscosity index of from 90- prising the steps of passing saidfeedstock, together with 160, thereafter passing said material ofimproved visthe hydrogen, over a dewaxing catalyst comprising one cosityindex, together with hydrogen, over a dewaxing or more hydrogenatingcomponents selected from Groups catalyst comprising one or morehydrogenating coin- Vla and VIII of the Periodic Table incorporated witha ponents selected from Groups VIa and VIII of the crystallinedecationised mordenite having a sodium content of less than 2 percentwt., said mordenite having a Si :Al- O ratio of from 14:1 to 50:1, at atemperature of from 450 to 950 F., a pressure of 100 to 3000 p.s.i.g., aspace velocity of 01-200 v./v./hr. and a hydrogen treating rate of50030,000 s.c.f./b., at which there is produced a material of reducedwax content boiling above 350 C. and having a reduced pour point,thereafter passing the feedstock having a reduced pour point, togetherwith hydrogen, over a viscosity index improvement catalyst comprisingone or more hydrogenating components selected from Groups VIa and VIIIof the Periodic Table, on a refractory oxide support, at a temperatureof from 650 to 850 F., a pressure of from 1000 to 3000 p.s.i.g., a spacevelocity of 0.1 v./v./hr. and a hydrogen treating rate of 2000-10,000s.c.f./b., at which there is provided a material of reduced aromaticReferences Cited UNITED STATES PATENTS 2/1968 Reid 208-- 7/ 1968 Gladrowet al. 208-111 HERBERT LEVINE, Primary Examiner US. Cl. X.R.

208-18, 111, DIG. 2

UNITED Y STATES IPIATENTIA OFFICE I I CERTIFICATE ()ECORRECTION PetentNo. v3,663,423 5 Dted May "16, 197 2 In 'entofls) Robert Neil Bennett,Richard Nigel Parker'en'd Bernard Whiting Burbidge v I v It; iscertified that; ferr'orappears in the above-identified patent "and thatsaid LettersPatent arehe-reby Corrected as shown below:

Col. 7, Table r, v right-hand column headed "Pour, Point 31 o' I I for"-70" read -v-- 1.0 v

Col. 8, Line 45, I i for "30 0 90"] I read signed endesealed thiSfSth-deyi of' Deoembe'r- L), Attestt EDWARD'MQFLETCI-IERJR. ROBERTGOTTSCHALK f Attesting Officer I Commissioner of Patents FORM PO-1(10-69) v r r f USCbMM-DC scam-p65 e u.s. eoyennmm PRINTINGOFFICE: i9590-386-334

